Rod-Pump Controller Using Electrical Signals for Pump-Off Detection
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Solution Overview
Problem
Existing pump-controllers for oil and gas wells are expensive due to the use of specialized sensors, leading to inefficiencies and potential damage from pumped-off conditions, which result in wasted energy, premature wear, and additional mechanical damage.
Innovation Solution
A cost-effective controller using electric current, fuel, or air usage sensors, combined with tubing pressure and polish rod temperature monitoring, to detect pump-off conditions and adjust pump operation parameters, thereby maintaining peak efficiency and reducing energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If specialized sensors (load cells, encoders) are used to detect pump-off conditions, then detection reliability is improved, but device cost and complexity increase
Solution Approach 1:
The patent replaces complex mechanical sensors (load cells, encoders) with electrical parameter monitoring. The controller detects pump-off conditions by analyzing electrical characteristics such as current draw patterns, voltage fluctuations, and power consumption of the motor, thereby detecting pump-off conditions reliably without specialized mechanical sensors
Solution Approach 2:
The patent uses electrical parameter patterns as proxies for mechanical state. By monitoring and analyzing the electrical signature (current, voltage, power) of the motor during operation, the system creates an electrical copy or representation of the mechanical pumping state, allowing indirect detection of pump-off conditions through readily available electrical measurements
2Measurement precision
If specialized sensors are used to detect pump-off conditions, then detection accuracy is improved, but installation cost and difficulty increase
Solution Approach 1:
The patent leverages the existing electrical system components (motor, controller, power supply) to provide the detection function. The motor's own electrical characteristics during operation serve as the detection signal, eliminating the need for separate sensing systems and their associated installation requirements
Solution Approach 2:
The electrical parameters monitored (current, voltage, power) serve multiple functions: they control motor operation, protect against faults, and simultaneously provide pump-off detection. This multi-functionality eliminates the need for dedicated detection hardware and simplifies installation by using already-present electrical measurement points
3Productivity
If the pump continues to operate in pumped-off conditions, then productivity is maintained, but energy waste and mechanical damage increase
Solution Approach 1:
The controller continuously monitors electrical parameters and uses this feedback to detect pump-off conditions. When a pump-off condition is detected through analysis of current draw patterns or power consumption anomalies, the controller responds by shutting down the motor, thereby preventing further energy waste while protecting the pumping system
Solution Approach 2:
The system dynamically adjusts pump operation based on real-time electrical parameter analysis. Rather than continuous operation, the pump operates only when electrical characteristics indicate normal pumping conditions, allowing the system to adapt its operation to actual pumping needs and avoid energy waste during pump-off conditions
4Productivity
If the pump operates continuously without monitoring, then productivity is maintained, but mechanical wear and damage increase
Solution Approach 1:
The controller uses real-time feedback from electrical parameter monitoring to detect abnormal operating conditions indicative of pump-off states. This feedback mechanism enables timely shutdowns that prevent excessive mechanical wear on rods, tubing, and pump components, thereby extending equipment service life while maintaining productivity during normal operation
Data Source
AI summary
A rod-pump control device is disclosed. The claimed rod-pump control device uses fuel or air usage for gas units, and can use pressure. The sensors work as the primary trigger to indicate a pump-off condition on an oil and gas well. These sensors can be used as stand-alone triggers or in conjunction with other sensors to more accurately monitor pump efficiency. When the pump-controller starts to indicate an inefficient pump condition, it will remove power to disengage an electric clutch or send a signal to an engine controller to stop. An adjustable algorithm will use percentage change of off time, dependent on actual run time compared to a user definable target time to keep the pump operating at peak efficiency.